1. Technical Field
The technical field relates generally to interlocks for isolating electrical power sources and more particularly to their application to power cables and cable connectors on motor vehicles.
2. Description of the Problem
Hybrid-electric and electric vehicles provide storage of electrical power in batteries or on capacitors. Such batteries and capacitors have terminal to terminal voltage differentials which are greater by more than an order of magnitude than chassis batteries used on most contemporary trucks and cars. Cables connected to the batteries can exhibit these relatively high potentials on terminal plugs at points of connection to the vehicle electrical system.
In applications where personnel are potentially exposed to high voltages, interlock circuits have been used to isolate the high voltage source when connectors are opened and could potentially expose terminals which could carry high voltages. U.S. Pat. No. 5,949,806 (Ness et al.) teaches one such High Voltage Interlock Circuit. In addition, connectors used in high voltage application have been modified to support addition of an interlock circuit which is interrupted if the connector sections are not securely fastened. For motor vehicles such connectors are commonly provided in four and five wire versions. In a four wire cable, two wires are used for the high voltage circuit and two wires are used for the voltage interlock circuit. In a five wire connector, three wires are used for high voltage and two for the interlock circuit. Both types of connectors provide shielding.